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The Temagami Magnetic Anomaly, also called the Temagami Anomaly or the Wanapitei Anomaly, is a
The Temagami Magnetic Anomaly is egg-shaped, long and wide. The central section has the greatest amplitude and an east–west strike.
The Temagami Magnetic Anomaly was first found in the late 1940s during a magnetic survey by Norman Bell Keevil.
The western portion appears smoother in character while the eastern section is long and narrow. With an areal extent of 50 x 15 km, it reaches a magnitude of approximately 10,000 nanoteslas, making it one of the largest positive anomalies in North America. The eastern section coincides with a small positive gravity anomaly, indicating the presence of dense rocks at depth.Kawohl, Alexander et al. (2017
What's inside the Temagami geophysical anomaly, Sudbury District, Ontario?
SGA Québec 2017 extended abstract, Vol. 4, 1543-1546. The anomaly was discovered by a magnetic survey and a gravity survey. In 2014, a 2200m borehole was drilled at Afton Township where the anomaly is at its maximum. Analysis of the lowest most rocks indicated similarities with the quartz diorite dykes found at the Sudbury Igneous Complex, which were likely created at the same time as the Sudbury impact event.
The Temagami Magnetic Anomaly, also called the Temagami Anomaly or the Wanapitei Anomaly, is a magnetic anomaly
In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying ...
resulting from a large buried geologic structure in the Canadian Shield
The Canadian Shield ( ), also called the Laurentian Shield or the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), th ...
near Temagami, Ontario, Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
. It stretches from Lake Wanapitei in the west to Bear Island in Lake Temagami.
The Aboriginal community of Teme-Augama Anishnabai lies partly within the Temagami Magnetic Anomaly, including the Temagami First Nation on Bear Island. Located nearby are a number of other geological structures, including the Sudbury Basin
The Sudbury Basin (), also known as Sudbury Structure or the Sudbury Nickel Irruptive, is a major geology, geological structure in Ontario, Canada. It is among the oldest- and largest-known List of impact structures on Earth, impact structures ...
, the Lake Wanapitei impact crater, and the Temagami Greenstone Belt.
Discovery and structure
The Temagami Magnetic Anomaly is egg-shaped, long and wide. The central section has the greatest amplitude and an east–west strike.
The Temagami Magnetic Anomaly was first found in the late 1940s during a magnetic survey by Norman Bell Keevil.
The western portion appears smoother in character while the eastern section is long and narrow. With an areal extent of 50 x 15 km, it reaches a magnitude of approximately 10,000 nanoteslas, making it one of the largest positive anomalies in North America. The eastern section coincides with a small positive gravity anomaly, indicating the presence of dense rocks at depth.Kawohl, Alexander et al. (2017What's inside the Temagami geophysical anomaly, Sudbury District, Ontario?
SGA Québec 2017 extended abstract, Vol. 4, 1543-1546. The anomaly was discovered by a magnetic survey and a gravity survey. In 2014, a 2200m borehole was drilled at Afton Township where the anomaly is at its maximum. Analysis of the lowest most rocks indicated similarities with the quartz diorite dykes found at the Sudbury Igneous Complex, which were likely created at the same time as the Sudbury impact event.
See also
* Maple Mountain (Ontario) * Bangui magnetic anomaly * Kursk Magnetic Anomaly * Ishpatina RidgeReferences
{{coord, 47.0, -80.2, region:CA-ON_scale:100000, display=title, name=Temagami magnetic anomaly Geology of Temagami Magnetic anomalies